mirror of
https://github.com/PurpleI2P/i2pd.git
synced 2026-10-15 04:30:44 +00:00
common BEncoded parser
This commit is contained in:
orignal
+181
-230
@@ -10,6 +10,7 @@
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#include <stdlib.h>
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#include <charconv>
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#include <fstream>
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#include <functional>
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#include "Log.h"
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#include "FS.h"
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#include "ClientContext.h"
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@@ -19,6 +20,109 @@ namespace i2p
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{
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namespace torrents
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{
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// BEncoded
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static std::pair<std::string_view, size_t> ExtractByteString (std::string_view buf)
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{
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auto pos = buf.find (':');
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if (pos != std::string_view::npos)
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{
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size_t len = 0;
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auto res = std::from_chars(buf.data(), buf.data() + pos, len);
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if (res.ec == std::errc())
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{
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size_t totalLength = len + pos + 1;
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if (totalLength <= buf.length ())
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return { buf.substr (pos + 1, len), totalLength };
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}
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}
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return { std::string_view{}, 0 };
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}
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static std::pair<int64_t, size_t> ExtractInteger (std::string_view buf)
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{
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if (buf[0] == 'i')
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{
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auto pos = buf.find ('e');
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if (pos != std::string_view::npos)
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{
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int64_t value = 0;
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auto res = std::from_chars(buf.data() + 1, buf.data() + pos, value);
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if (res.ec == std::errc())
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return { value, pos + 1 };
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}
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}
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return { 0, 0 };
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}
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static size_t ParseBEncoded (std::string_view buf); // recursive
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static size_t ParseDictionary (std::string_view buf, std::function<size_t (std::string_view key, std::string_view buf)> handler = nullptr)
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{
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if (buf[0] != 'd') return 0;
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buf = buf.substr (1);
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size_t len = 1;
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while (!buf.empty () && buf[0] != 'e')
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{
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auto [key, offset] = ExtractByteString (buf);
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if (!offset) break;
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len += offset;
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buf = buf.substr (offset);
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offset = 0;
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if (handler)
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offset = handler (key, buf);
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if (!offset)
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offset = ParseBEncoded (buf);
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if (!offset) break;
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len += offset;
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buf = buf.substr (offset);
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}
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if (buf[0] == 'e') len++;
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return len;
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}
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static size_t ParseList (std::string_view buf, std::function<size_t (std::string_view buf)> handler = nullptr)
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{
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if (buf[0] != 'l') return 0 ;
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buf = buf.substr (1);
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size_t len = 1;
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while (!buf.empty () && buf[0] != 'e')
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{
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size_t l = 0;
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if (handler)
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l = handler (buf);
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if (!l)
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l = ParseBEncoded (buf);
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if (!l) break;
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len += l;
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buf = buf.substr (l);
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}
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if (buf[0] == 'e') len++;
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return len;
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}
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static size_t ParseBEncoded (std::string_view buf)
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{
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if (buf.empty ()) return 0;
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size_t ret = 0;
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switch (buf[0])
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{
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case 'i': // interger
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return ExtractInteger (buf).second;
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break;
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case 'l': // list
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return ParseList (buf);
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break;
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case 'd': // dictionary
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return ParseDictionary (buf);
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break;
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default: // byte string
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return ExtractByteString (buf).second;
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}
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return ret;
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}
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//------------------------------------
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Piece::Piece (size_t size, const uint8_t * hash):
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m_Size (size), m_Data (nullptr)
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{
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@@ -56,80 +160,20 @@ namespace torrents
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Torrent::Torrent (std::string_view buf):
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m_Length (0), m_PieceLength (0), m_Interval (0)
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{
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// parse top level dictionary
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if (buf[0] != 'd') return;
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buf = buf.substr (1);
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while (!buf.empty () && buf[0] != 'e')
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{
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auto [key, offset] = ExtractByteString (buf);
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if (!offset) break;
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buf = buf.substr (offset);
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if (key == "announce")
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ParseDictionary (buf, [this](std::string_view key, std::string_view buf)->size_t
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{
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auto [announce, l] = ExtractByteString (buf);
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if (!l) break;
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m_Announce = announce;
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buf = buf.substr (l);
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}
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else if (key == "info")
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{
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size_t l = ParseInfo (buf);
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if (!l) break;
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// calculate info hash
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uint8_t digest[SHA_DIGEST_LENGTH];
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SHA1 ((const uint8_t *)buf.data (), l, digest);
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// convert info hash to hex chars
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BIGNUM * bn = BN_bin2bn (digest, SHA_DIGEST_LENGTH, nullptr);
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char * str = BN_bn2hex (bn);
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if (str)
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if (key == "announce")
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{
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m_InfoHash = str;
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OPENSSL_free (str);
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auto [announce, l] = ExtractByteString (buf);
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if (l) m_Announce = announce;
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return l;
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}
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BN_free (bn);
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buf = buf.substr (l);
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}
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else
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{
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size_t l = Skip (buf);
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if (!l) break;
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buf = buf.substr (l);
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}
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}
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else if (key == "info")
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return ParseInfo (buf);
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return 0;
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});
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}
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std::pair<std::string_view, size_t> Torrent::ExtractByteString (std::string_view buf) const
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{
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auto pos = buf.find (':');
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if (pos != std::string_view::npos)
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{
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size_t len = 0;
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auto res = std::from_chars(buf.data(), buf.data() + pos, len);
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if (res.ec == std::errc())
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{
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size_t totalLength = len + pos + 1;
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if (totalLength <= buf.length ())
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return { buf.substr (pos + 1, len), totalLength };
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}
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}
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return { std::string_view{}, 0 };
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}
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std::pair<int64_t, size_t> Torrent::ExtractInteger (std::string_view buf) const
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{
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if (buf[0] == 'i')
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{
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auto pos = buf.find ('e');
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if (pos != std::string_view::npos)
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{
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int64_t value = 0;
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auto res = std::from_chars(buf.data() + 1, buf.data() + pos, value);
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if (res.ec == std::errc())
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return { value, pos + 1 };
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}
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}
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return { 0, 0 };
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}
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size_t Torrent::ParsePieces (std::string_view buf)
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{
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@@ -144,101 +188,50 @@ namespace torrents
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size_t Torrent::ParseInfo (std::string_view buf)
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{
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if (buf[0] != 'd') return 0;
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buf = buf.substr (1);
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size_t len = 1;
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while (!buf.empty () && buf[0] != 'e')
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size_t len = ParseDictionary (buf, [this](std::string_view key, std::string_view buf)->size_t
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{
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if (key == "length")
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{
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auto [value, l] = ExtractInteger (buf);
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if (l) m_Length = value;
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return l;
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}
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else if (key == "name")
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{
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auto [name, l] = ExtractByteString (buf);
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if (l) m_Name = name;
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return l;
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}
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else if (key == "piece length")
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{
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auto [value, l] = ExtractInteger (buf);
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if (l) m_PieceLength = value;
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return l;
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}
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else if (key == "pieces")
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{
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if (m_PieceLength > 0 && m_Length > 0)
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m_Pieces.reserve (m_Length/m_PieceLength + 1);
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return ParsePieces (buf);
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}
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return 0;
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});
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if (!len) return 0;
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// calculate info hash
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uint8_t digest[SHA_DIGEST_LENGTH];
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SHA1 ((const uint8_t *)buf.data (), len, digest);
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// convert info hash to hex chars
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BIGNUM * bn = BN_bin2bn (digest, SHA_DIGEST_LENGTH, nullptr);
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char * str = BN_bn2hex (bn);
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if (str)
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{
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auto [key, offset] = ExtractByteString (buf);
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if (!offset) break;
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len += offset;
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buf = buf.substr (offset);
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if (key == "length")
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{
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auto [value, l] = ExtractInteger (buf);
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if (!l) break;
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len += l;
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m_Length = value;
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buf = buf.substr (l);
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}
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else if (key == "name")
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{
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auto [name, l] = ExtractByteString (buf);
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if (!l) break;
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len += l;
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m_Name = name;
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buf = buf.substr (l);
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}
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else if (key == "piece length")
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{
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auto [value, l] = ExtractInteger (buf);
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if (!l) break;
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len += l;
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m_PieceLength = value;
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buf = buf.substr (l);
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}
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else if (key == "pieces")
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{
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if (m_PieceLength > 0 && m_Length > 0)
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m_Pieces.reserve (m_Length/m_PieceLength + 1);
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size_t l = ParsePieces (buf);
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if (!l) break;
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len += l;
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buf = buf.substr (l);
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}
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else
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{
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size_t l = Skip (buf);
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if (!l) break;
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len += l;
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buf = buf.substr (l);
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}
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m_InfoHash = str;
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OPENSSL_free (str);
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}
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if (buf[0] == 'e') len++;
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BN_free (bn);
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return len;
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}
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size_t Torrent::Skip (std::string_view buf)
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{
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if (buf.empty ()) return 0;
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size_t ret = 0;
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switch (buf[0])
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{
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case 'i': // interger
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return ExtractInteger (buf).second;
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break;
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case 'l': // list
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buf = buf.substr (1); ret++;
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while (buf[0] != 'e')
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{
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auto l = Skip (buf);
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if (!l) break;
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ret += l;
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buf = buf.substr (l);
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}
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ret++;
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break;
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case 'd': // dictionary
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buf = buf.substr (1); ret++;
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while (buf[0] != 'e')
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{
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auto l = ExtractByteString (buf).second; //key
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if (!l) break;
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ret += l;
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buf = buf.substr (l);
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l = Skip (buf);
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if (!l) break;
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ret += l;
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buf = buf.substr (l);
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}
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ret++;
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break;
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default: // byte string
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return ExtractByteString (buf).second;
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}
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return ret;
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}
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i2p::http::HTTPReq Torrent::GetTrackerRequest () const
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{
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i2p::http::HTTPReq req;
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@@ -249,91 +242,49 @@ namespace torrents
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void Torrent::ParseTrackerResponse (std::string_view buf)
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{
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// reponse is dictionary
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if (buf[0] != 'd') return;
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buf = buf.substr (1);
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while (!buf.empty () && buf[0] != 'e')
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{
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auto [key, offset] = ExtractByteString (buf);
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if (!offset) break;
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buf = buf.substr (offset);
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if (key == "interval")
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ParseDictionary (buf, [this](std::string_view key, std::string_view buf)->size_t
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{
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auto [value, l] = ExtractInteger (buf);
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if (!l) break;
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m_Interval = value;
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buf = buf.substr (l);
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}
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else if (key == "peers")
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{
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size_t l = ParsePeers (buf);
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if (!l) break;
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buf = buf.substr (l);
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}
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else
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{
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size_t l = Skip (buf);
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if (!l) break;
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buf = buf.substr (l);
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}
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}
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if (key == "interval")
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{
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auto [value, l] = ExtractInteger (buf);
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if (l) m_Interval = value;
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return l;
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}
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else if (key == "peers")
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return ParsePeers (buf);
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return 0;
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});
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}
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size_t Torrent::ParsePeers (std::string_view buf)
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{
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m_Peers.clear ();
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// peers is list of dictionaries
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if (buf[0] != 'l') return 0 ;
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buf = buf.substr (1);
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size_t len = 1;
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while (!buf.empty () && buf[0] != 'e')
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{
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size_t l = ParsePeer (buf);
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if (!l) break;
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len += l; buf = buf.substr (l);
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}
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if (buf[0] == 'e') len++;
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return len;
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return ParseList (buf, std::bind (&Torrent::ParsePeer, this, std::placeholders::_1));
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}
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size_t Torrent::ParsePeer (std::string_view buf)
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{
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if (buf[0] != 'd') return 0;
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std::string peerID;
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std::shared_ptr<const i2p::client::Address> addr;
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buf = buf.substr (1);
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size_t len = 1;
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while (!buf.empty () && buf[0] != 'e')
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{
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auto [key, offset] = ExtractByteString (buf);
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if (!offset) break;
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len += offset;
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buf = buf.substr (offset);
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if (key == "id") // peer_id
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size_t ret = ParseDictionary (buf, [&peerID, &addr](std::string_view key, std::string_view buf)->size_t
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{
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auto [id, l] = ExtractByteString (buf);
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if (!l) break;
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peerID = id;
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len += l; buf = buf.substr (l);
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}
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else if (key == "ip") // address
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{
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auto [address, l] = ExtractByteString (buf);
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if (!l) break;
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addr = i2p::client::context.GetAddressBook ().GetAddress (address);
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len += l; buf = buf.substr (l);
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}
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else
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{
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size_t l = Skip (buf);
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if (!l) break;
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len += l; buf = buf.substr (l);
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}
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}
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if (buf[0] == 'e') len++;
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if (addr)
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if (key == "id") // peer_id
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{
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auto [id, l] = ExtractByteString (buf);
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if (l) peerID = id;
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return l;
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}
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else if (key == "ip") // address
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{
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auto [address, l] = ExtractByteString (buf);
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if (l) addr = i2p::client::context.GetAddressBook ().GetAddress (address);
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return l;
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}
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return 0;
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});
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if (ret && addr)
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m_Peers.emplace_back (std::pair{ peerID, addr });
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return len;
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return ret;
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}
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PeerConnection::PeerConnection (i2p::client::I2PService * owner, std::shared_ptr<i2p::stream::Stream> stream):
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@@ -61,13 +61,10 @@ namespace torrents
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private:
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std::pair<std::string_view, size_t> ExtractByteString (std::string_view buf) const;
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std::pair<int64_t, size_t> ExtractInteger (std::string_view buf) const;
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size_t ParsePieces (std::string_view buf);
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size_t ParseInfo (std::string_view buf);
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size_t ParsePeers (std::string_view buf);
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size_t ParsePeer (std::string_view buf);
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size_t Skip (std::string_view buf);
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private:
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